In a conventional liquid crystal display panel, mostly a white-light-emitting device which emits a continuous spectrum is used as a backlight source, and a polarizer at a lower portion of the liquid crystal panel is used to obtain light linearly-polarized in a single direction, and a color filter (CF) at an upper portion of the liquid crystal panel is used to obtain light of three primary colors, i.e. red, green and blue (RGB), whereby achieving display of various colors within a color gamut. This method will cause the light waves of the natural light in a direction perpendicular to the polarization direction of the polarizer to be filtered, and in the meantime, the filter only allows light of a single color to be emitted, which results in further loss of the backlight. Therefore, there is a need to provide a new backlight mode which does not need a polarizer or a color filter.